Spring switch



E. A. HOOPES SPRING SWITCH Filed Jan. 30,1933

3 Sheets-She et 1 Dec. 17, 1935. E. A. HooEs I I 2,024,362

SPRING SWITCH Filed Jan. 30, 1933 3 Sheets-Sheet 2 v Mm)- Zr/zaa: J. 15790;:

Dec. 17, 1935. E. A. HOOPES 5 3 SPRING SWITCH Filed Jan. so, 1955 s Sheets-Sheet s [fl 22d! A. A m a:

Patented nae. i 17, 1935 1 UNITED STATES PATENT OFFlCE SPRING SWITCH Ernest A. Hoopes, Des Moines, Iowa, to Guy 1!. Hall, Milwaukee, Wis.

Application January so, 1933, Serial No. 654,129

12 Claims. (o1. 1 -100) This invention relates to and consists in certain improvements on and additions to the general form of switch devices disclosed in my application for United States Letters Patent filed Au ust 17, 1931, Serial Number 557,557.

In my said application I disclosed means for provide an improved spring switch in which compression required for springing the switcl'rto open position maybe applied to the upper or convex side of the spring, and further in this connection to provide such means whereby pressure upon the convex side of the main spring may be limited to the longitudinal central portion thereof to aid'in straightening transversely the portion thus engaged to aid in moving the switch to open position.

A further object is. to provide improved and simplified means for mechanically applying pressure alternately to the main spring in such positions as-to in one movement cause it to snap to open position, and in another movement cause it to'snap to closed position.

A further object is to provide means of-simple, durable and inexpensive construction for varying the transverse curvature of the main spring, whereby it may be strengthened or weakened to suit the requirements against bending in a direction toward its upper or convex side.

A further object is to provide an improved method of forming a spring of the character elnployed in this device substantially straight iongitudinally and substantially concavo-convx transversely, and which is intended to beoperated by being bent transversely, and whereby the life of the said spring is naturally increased, and

whereby the said spring may be bent upwardly or toward its convex side when a transverse portion thereof is straightened out with a amount of crystallization and without weakening the spring at the bent portion.

My invention consists in the construction, ar-

portion broken away. In this figure the dotted lines show'the position of the parts when-the switch is opened.

Figure 3 shows an--end elevation-of same. 1 Figure 4 shows a top or plan view of a modified form of my improved switch illustrating the means for adjusting the curvature of the main spring.

Figure 5 is a side elevation of same. Figure 6 is an end elevation of same with the main spring shown at its maximum degree of 10 curvature; and Figure '7 shows a similar view showing-the main spring at a less degree of curvature. T

Figure 8 shows a perspective view of the main spring flat in cross section and curved longitudi- 1 nally illustrating the shape ofthe spring in a preliminary stage'of my improved niethod of forming same.

Figure 9 shows a similar view illustrating the main springin its completed form. 9

Figure 10 shows a similar view illustrating the normal curvature transversely of the main spring, and by .dotted lines the curvature transversely when mounted in a switch device ready for use.

Figure 11 shows a side elevation of another 25 modification of my improved switch.

Figure 12 shows a similar view with the switch in a closed position; and

Figure 13 shows a sectional |3l3 of Figure 12.

Figure 14 shows a transverse sectional view through the concavo-convex spring and the conical spring, as shown in Figure 2, and illus-' view on the line trating by dotted lines the curvature given-to the concave-convex spring by the pressure of 35 the conical spring. a

Figure 15 shows an isometric view .of the-concavo-convex spring in the position which it assumes when the switch is open, and illustrating a modified form of this-spring in which the 40 longitudinal edges are relatively straight as compared with the transverse curvature of the .body portion thereof. I

Figure 16 shows .a sectional view of same on the line l6-l6 of Figure 15; and

Figure 17 shows a side view of a pressure operated switch embodying my invention, and illustrating a modified form thereof in which the base which supports the concavo-convex spring-- is tilted at one end by' pressure operated mechanism to effect opening and closing of the switch. The dotted lines show the switch in closed position.

Referring to the accompanying drawings, and particularly to Figures 1 and 2 thereof, it will a be seen that my improved switch comprises a base 20. On one end of this base there is a raised spring seat member 2| arched upwardly at its longitudinal central portion as shown in Figure 3. On the opposite end of the base there ported on the seat 2| to its free end. This main spring is secured to the seat by a plate 24 held in place by screws 25 inserted into the seat portion 2|.

At the free end of the spring 23 I have applied a cross piece 26 straight transversely, and which holds the adjacent portion of the main spring 23 in a straight transverse position at the edge of the cross piece 26 adjacent to the central portion of the main spring 23.

Extended through this cross'piece 26 is a lever 21, with one end projecting straight outwardly from the spring 23 and provided with acontact device 28. The other end of. the lever 21 projects under the main spring 23 where'it is formed with a cup-shaped member 29, and'inthis cup shaped member is an extensible coil spring of conical shape indicated by the reference numeral 30. Its upper end bears against the under or concave side of the spring 23. v

' The movable pin 3| is applied to the under surface of the lever 21 below the spring 30. This prevents downward movement of the lever 21 at the point where it is applied.-

For causing this switch to snap from its closed a to its open'position, and for causing it to return to its closed position, I haveprovided the following mechanism:

On opposite sides of the base 20 are two upright supports 32 between which there is pivoted a rod 33. Fixed to this rod isa lever 34 having a curved portion, 35 arranged adjacent to but slightly spaced apart from the rod ,33 in a direction toward the fixed end of the main spring 23. The other end of the lever 34 projectsforwardly over the lever 21 and a cushioning spring 36 is fixed to its under surface to engage the cross piece 26.

In practical operation with this form of the invention and assuming that the parts are in the position shown by solid lines in Figure 2, then the main spring 23 on account of its transverse concavo-convex curvature tends to yieldingly remain in a straight line, whereas the pressure of the spring 30 against the under or concave side of the main spring tends to move its free end upwardly, but the pressure of the spring 30 is so proportioned that it of itself will not bring a portion of the spring 23 to a substantially straight line position transversely, and hence normally the parts will remain in the position shown in Figure 2.

When, however, it is desired to snap the switch open pressure may be applied to the lever 34 in a direction tending to press the curved portion 35 thereof downwardly against the longitudinal central portion of the main spring 23. This pressure tends to straighten .-out transversely that portion of. the main spring 23, and when the main spring and the lever 21 carried thereby to spring rapidly to the position shown by dotted lines in said figure, and separating the contacts 22 and 28, and the parts will remain in that position until the lever 34 is again operated to cause the cushioning spring 36' carried thereby to press downwardly upon the outer end of the 'main spring 23, whereupon the switch is moved to closed position.

In the modification illustrated in Figures 4 to 7 inclusive, I have shown a means whereby a main spring may be employed of a maximum degree of curvature transversely to thereby be relatively easily flexed in the direction of its upper or convexside, and which may be readily, quickly and easily adjusted by an operator to decrease its curvature transversely to thereby make it relatively harder to flex upwardly in the direction of its convex side.

This mechanism comprises a curved support 2 I having its upper or bearing face at 31 made on a substantially less curvature than the normal curvature of the main spring 23.

Mounted on top of the main spring above the seat portion 2| isa small spring leaf 38 of substantially the same material and having substantially the same normal curvature as that of the main spring 23. Above the leaf 38 is a saddle member 39 of bendable material and normally having a considerably greater curvature transversely than that of the seat portion 31. At the opposite sides of this saddle member 39 are two screws 40 extended through the saddle member and screwed into the seat member 2|, and whereby the saddle member, the main spring and the spring leaf 38 may all be bent to any degree .of

transverse curvature less than normal up to the 85 position shown in Figure 6, which is substantially concentric with the curvature 31 of the seat 2|. Obviously by this arrangement the amount of resistance applied to the main spring opposing the opening movement of the switch may be 40 varied to suit the requirements from a minimum amount of pressure applied to the rod 3| for opening the switch when the transverse curvature of the main spring is relatively flat, to a maximum amount of pressure required to open the switch when the curvature of the main spring is at its minimum amount, as shown in Figure 6. In the modification shown in Figures 10 to 13 inclusive I have shown a substantially U-shaped leaf spring 4| in place of the conical coil spring '30 before described, and for the same purpose, and I have also disclosed a supporting rod 42 engaging the socket 29 on the lever 21 mounted at its lower end in a stationary support 43.

I have also shown a portion of the main frame at 44 made of spring material to normally incline the spring seat 2| downwardly at its forward end, as shown in Figure 10, to thereby apply a yielding downward pressure to the top or convex side of the main spring, tending to flatten the main spring out transversely, and to co-operate with the spring 4| and its support 42 in moving the switch to open position.

In this form of the invention I have shown as a means for moving the switch to a closed position a rod 45 connected with a movable member 46 and engaging the front end of the seat 2|, so that an upward pressure upon said rod will tilt the seat 2| to the position shown in Figure 12, and during this tilting movement, the main spring, on account of its resiliency, will snap the switch to closed position.

In Figure 13 I have illustrated a modified form of means for clamping the main spring to the spring seat, comprising a saddle device 46 to pass 2,024,302 over thetop of the main spring with a substanrounded hinge member '55 in a round groove in the frame H 56' that the opposite end tially flat surface in engagement with the main spring, and having extensions 41 at its sidesfex tending downwardly beyond the mainspring, and

r the base 54- fiiyh'ave a limited up and down movement.- On its opposite end there is aypro-i a cross piece 48 connecting said extengons jecting shoulder iii inserted in a notch 51 in the Seated in the cross piece 48 is a set screw 49 engaging a block 59, the curvaturevof the upper surface of which is substantially the same as that of the adjacent portion of the main spring.

By this means the main spring is firmly clamped on the support at least at its -;longitudinal central portion, and at the same time the side edges adjacent to the clamped portion are free' to move upwardly. This construction operates to relieve the main spring of unnecessary strains and stresses such as might occur if1it were clampedon all sides.

In Figure 14 I have illustrated a feature of my invention which is of importance in increasing the life .of the main concavo-convex spring and increasing the efliciency of the switch device.

The conical shaped .coil spring 30 is of such size and shape that it will'engage only the longitudinal central portion of the concavo-convex spring 23. When pressure is applied to the spring 30 in,an upwarddirection by pressure upon the rod-3| then the first effect of this pressure is to'cause the spring 23 to be arched upwardly at its central portion, as shown by dotted lines in Figure 14. This causes the spring 23 to be curved along an arch pf less diameter, thereby the spring 23 is stiffened against the force of pressure tending to move the spring 23 toa straight line transversely at the point where the spring 30'engagesit-. Thenfwhen pressure is applied to the spring 23 sufliciently to move it to a straight line transversely at one point, the

switch will snap open more rapidly than though itscentral portion had not previously been arched upwardly, as shown by dotted lines in said figure. v

One of the advantages of this construction is that the spring 23 need not be given as great a degree of initial'curvature before being assembledin the switch as would be necessary but for this action of the spring 30 in arching thespring 23' what exaggerated for clearness and illustration,

but I have foundin'practice that by leaving the edge portions 23a relatively straight transversely and arching only the central portion between said edges, the-tendency for the edge portions to crystallize and break after long use is greatly minimized. f I

In Figure 1'? of the drawings, I-have shown a modified form ofmy improved switch especially adapted for use with pressure operated mechanisms, and which consists of a frame or casing indicated generally by the numeral 5l -Mounted in this frame is an expansible corrugated cylinvex spring 23 and associated parts is the same as that illustrated in Figures 4 and 5.

However, the base 54 upon which the spring 23 is mounted is provided at one end with a frame 5| to permit a limited up' and down movement of this end of the base 54.. A coil spring 58 bears upon the top of the spring 23 directly in line with the expansible cylinder 52.

In operation with this form of the invention,

.thespring 58 normally holds the switch device in position shown by solid lines in Figure 17. Then when pressure is applied to the expansible cylinder 52, it elevates the adjacent end of the base 52 as shown by dotted lines, which overcomes the pressure of the spring 58 and permits the base 54 to move upwardly. When this base moves upwardly, then the relative pressure of the spring 3|) is overcome by the tendency of the spring 23 to assume its straight line position, and the switch moves to a closed position as shown by dotted lines.

My improved method of forming the main spring is as follows:

I first take a piece of flat spring metal, slightly 25 tapered toward one end. I then bend it longitudinally in the manner illustrated in Figure 8, 'and cause it to become set in that position, preferably by the usual heat treatment for such purposes. I then bend it to the position shown in .30 Figure 9, giving it substantially concavo-convex shape transversely, and when this is done its body will naturally assume a substantially straight line position longitudinally, and Ithen cause the spring to be set in this position preferably by the customary heat treatment. I then clamp the relative sides of the main spring to a seat or support which has a less curvature than that of the curvature to which the spring was originally set, as illustrated in Figure 9. I then 40 apply pressure to the side edges of the spring to give it a less degree of curvature transversely, as shown by solid lines in Figure 10. The curvature of themain spring longitudinally, as shown in Figure 8, is midway between the positions of the spring when the switch is open and when the switch is closed, so that during this opening and closing movement of the switch a minimum amount of strains and stresses will be set up in the main spring.

In actual tests I'have found that where springs are employed like the main spring herein illustrated, but which are not set to the normal curvature illustrated in Figure 8, then in endurance tests the springs not set to the curvature illustrated in Figure 8 before being set to the curvaturc illustrated in Figure 9 will, during the snapping movement of the switch, crystallize and break much earlier or with a much less number of snapping movements than will occur when the spring is normally set to the position shown in Figure 8 before being normally set to the positio'n'shown in Figure 9.

Furthermore, I have found by actual tests that when the spring is normally set to a position shown in Figure 9, on a normal relatively large arc, and later clamped to position with a relatively'less arc transversely, thenthe life of the spring in its snapping switch action is greatly increased over springs which are normally set to the transverse curvature desired for use in the switch..

In repeated tests with main springs of this character I have caused the switch to be snapped from closed to open position and back more than 16 one million times, without showlng'any appreciable deterioration in the main spring or any appreciable difference in the amount of pressure which the main spring applies to the contacts when in closed position.

In practical use and with the form of the invention illustrated in Figures: 1 and 2, the resiliency of the main spring 23 tends to hold the contact 28 firmly against the contact 22.

The spring 30, however, in co-operation with the lever 21, tends to oppose the resiliency of the spring 23 and tends to move the contact 28 to open position. However, the spring 23 in this respect is stronger than the spring 30, and when both of these spring pressures are applied, the switch will remain in its closed position, as shown in-Figure 2. This switch could be moved to open position by pressure upon the rod 3| in an amount suflicient to bring a portion of the spring 23 to a straight line position transversely, whereupon the spring 23 would become so weakened that the spring 30 would rapidly snap the switch to its open position.

Instead, however, of applying upward pressure to the rod 3|, I have provided a means for snapping the switch to both open and closed positions with a. relatively small amount of power by providing the lever 34. When the handle end of this lever 34 is moved downwardly, then the curved portion 35 thereof presses against the central portion of the main spring against its top or convex side, and this tends to straighten out the main spring transversely at the point where this pressure is applied, and with a very slight amount of applied pressure at this-point. constant pressure of the spring 30 causes the switch to snap to open position where it will refree end of the spring downwardly against the action of the spring 30, andin the direction of the normal tendency of the spring 23 to move to a straight line position. Hence, a very slight amount of pressure applied to the cushion 36 will snap the switch back to closed position.

In the modified form illustrated in Figures 11 and 12 the main frame of the switch device is formed with a spring element 44 which normally tends to assume the position shown in Figure 11, and throws the switch to and holds it in openposition through the co-operation of the fulcrum pin 43. Then a means for applying pressure through the rod 45 is provided, which, when the pressure is applied, opposes the action of the spring 44, and permits the switch to snap to closed position, as illustrated in Figure 12.

In the accompanying claims I have used the expression, or its equivalent means for applying yielding pressure to the main spring in the direction of its convex side, and this is intended to cover any yielding pressure device applied to the spring in such a manner as to cause it to straighten out transversely at one portion, thereby greatly reducing its resiliency and permitting its easy snap to anopen position.

I claim as my invention: I

1. In a device of the class described, the combination of a spring substantially concavo-convex in cross section, means for supporting it, means for applying a yielding pressure to an unsupported portion of said spring in a manner tending to bend said portion in the direction of its convex side, but in an amount less than that required to bring said spring to a substantially straight line position transversely, and means for applying pressure to the convex side of said spring in an amount suflicient to bring said spring to a substantially straight line position trans- 5 versely, and whereby the said means for applying a yielding pressure to said spring will cause the unsupported portion of said spring to move rapidly in the direction in which it is forced by said yielding pressure means. 10

2. In a device of the class described, the combination of a spring substantially concavo-convex in cross section, means for supporting it, means for applying a yielding pressure to an unsupported portion of said spring in a manner 15 tending to bend said portion in the direction of its convex side but in an amount less than that required to bring said spring to a substantially straight line position transversely, and means for applying pressure to the convex side of said spring 20 between the supported portion and the portion where the said yielding pressure is applied in an amount sufiicent to bring said spring to a substantially straight line position transversely, and whereby said means for applying a yielding pressure to said spring will cause the unsupported portion of said spring-to move rapidly in the direction in which it is forced by said yielding pressure means.

3. In a device of the class described, the com- 39 bination ofa spring substantially straight longitudinally and substantially concavo-convex transversely and having a normal set which tends to return the spring from any position to a straight line position longitudinally, means for support- 35 ing it at one end, means for applying ,a yielding pressure to the concave side of its opposite end, and means for applying a pressure to the convex side of said spring, for-the purposes stated.

4. In a device of the class described, the com- 40 bination of a spring substantially straight longitudinally and substantially concave-convex transversely and having 'a normal set which tends to return the spring from any position to a straight line position longitudinally, a lever fulcrumed to one end ofsaid spring having a portion thereof projected adjacent the concave side of said spring, a yielding pressure device interposed between said lever and the concave side of said spring and said lever, and means for applying pressure to said spring in a direction tending to straighten it transversely at one point, for the purposes stated.

5. In a device of the class described, the combination of a spring substantially straight longitudinally and substantially concavo-convex transversely, means for applying pressure to a portion of the spring tending to move it in the direction of its convex side, and means for varying the curvature of said spring transversely to make it more or less rigid in opposing said pressure applying means.

6. In a device of the class described, the combination of a spring substantially concavo-convex in cross section, means for applying a yielding pressure to said spring tending to move it in the direction of its convex side, and means for applying pressure to the convex side of the spring tending to bring it to a straight line position transversely,

7. In a switch of the class described, the combination of a spring substantially straight longitudinally and substantially concavo-convex transversely, a second spring engaging the central longitudinal portion only of the concave side of the concave-convex spring, and means for applying pressure to said second spring in a direction tending to increase the curvature of the concaveconvex spring.

8. An improved switch comprising a base, means for pivotally supporting the base at one end, a spring substantially straight longitudinally and substantially concavo-convex transversely fixed at one end to'said base, a contact carrier on the free'end of said spring, a support engaging the concave side of said spring near its free end, and means for moving the free end of the base to open the switch when moved in one direction and to close it when moved in the opposite direction.

9. In a device of the class described, the combination of a spring substantially straight -longitudinally and substantially concave-convex transversely, a support for said spring having a spring engaging portion shaped to normally engage only the longitudinally central portion of said spring, and a spring adjusting device for adjusting the edge portions of said spring toward said support to increase its curvature transversely.

10. In a device of the class described, the combination of a spring substantially straight longitudinally and substantially concavo-convex,

transversely, a support for said spring having a spring engaging portion shaped to normally engage only the longitudinally central portion of said spring, a flexible saddle engaging the convex side of said spring, and screws passed through the saddle and seated in the support for adjusting the side portions of said spring toward the support to increase its curvature transversely.

11. In a device of the class described, the combination of a spring of a length materially greater than its width and substantially concave-convex transversely, a yielding pressure device applied to said spring in a manner tending to bend it in the direction of its convex side, and means for applying pressure to said spring in a direction for opposing the action of said yielding pressure device.

12. In a switch of the class described, a spring 20 

